This application proposes to develop two novel prophylactic and therapeutic non-viral gene transfer strategies that target pulmonary cells in vivo employing nanotechnology. The lung is especially well suited for these treatment strategies as direct contact with the environment provides a portal for inhalation administration of cDNA and siRNA conjugated nanoplexes. The emergence of drug-resistant strains of human influenza A and B viruses, as well as avian H5N1 influenza viruses with pandemic potential to one or both classes of approved antiviral agents underscores the importance of developing novel antiviral strategies. The primary objective of the R21 phase is to construct an electrostatic complex between a cationic nanoparticle (i.e., Gold Nanorods, GNR) and anionic genetic material (i.e., cDNA or siRNA). These nanoplexes will be engineered such that they can be taken-up and express bioactivity in large airway (i.e., bronchial) epithelial cells with little or no untoward cellular or pulmonary responses. The siRNA/cDNA constructs, which have just recently been synthesized, have dual actions of suppressing the translation of the influenza virulence factor, NS1, as well as independently stimulating type I interferon production through activation of the RIG-I pathway. Stimulation of this antiviral innate immune pathway occurs as a result of a triphosphate (PPP) moiety attached to the 5'end of the siRNA. We will preferentially administer the GNR-5'PPP-NS1siRNA or its counterpart cDNA nanoplexes to the tracheal and bronchial epithelium in vivo, thereby increasing the safety of the treatment. Extension of these nanotechnological approaches can also be applied to treat other infectious, as well as non-infectious acute lung injuries. The focus in the R33 phase will be to demonstrate the therapeutic efficacy of using 5'PPP-NS1siRNA and cDNA-nanoplex targeting of large airway epithelial cells in vivo before and during influenza. In addition to assessing the clearance of influenza virus from the respiratory tract, the R33 phase will specifically examine the ability of 5'PPP-NS1siRNA or cDNA-nanoplexes to stimulate innate antiviral immunity, resulting in alteration of the inflammatory cytokine milieu, adaptive immune response, and antibacterial host defense, as well as prevent or reduce the degree of viral induced respiratory injury and impairment of bacterial clearance. We predict that these large airway epithelial-targeted nanoplexes will lead to prophylactic and therapeutic options that can prevent or significantly reduce the morbidity and severity of symptoms of influenza including the highly pathogenic H5N1 "bird flu" and the risk of secondary bacterial pneumonia, which is the major cause of death secondary to influenza. It is our goal to have a nanoparticle mediated novel antiviral prophylactic and therapeutic strategy at the completion of the R33 phase available for Investigational New Drug filing with the FDA to go for Phase 1 clinical trials as a result of the experiments proposed in this application. PUBLIC HEALTH RELEVANCE: Influenza is one of the top killers of people in the USA and the world, and the emergence of drug-resistant strains of influenza virus (including the "Bird Flu") requires that we develop new preventative and treatment approaches to this disease. This application proposes to develop a novel method to transfer a gene (cDNA) or its immediate message (siRNA) to cells that line the large airways of the lung employing an aerosol inhaler. Attaching cDNA or siRNA to small (nanometer size) gold rods will help deliver the anti-influenza treatment to inside the airway cells where it will work. This treatment stimulates immunity against influenza virus, as well as interferes with the virus'ability to do damage to the airways.